MATLAB: Comments for Simulink signals and states do not appear in the C code.

Embedded Coder

I am making a control algorithm model in Simulink from which I want to generate readable (and highly-efficient) C code. I want to add comments in the generated C code for certain Simulink signals and states. I have tried to apply the method shown in the demo model 'rtwdemo_comments', but despite many attempts, I still have not managed to realize the comments in the C code.

In my model, I have added a description for the Simulink.Signal objects corresponding to a certain state and a signal, but the description does not pop up as a comment in the generated C code. How can this be accomplished?

Best Answer

The reason that your comments are not appearing in the generated code is due to the storage classes you have chosen for the Simulink.Signal objects. When the storage class is set to 'Auto', the data elements are subject to code generation optimizations. Since these Simulink.Signal objects are not declared on their own in the code, their comments do not make it into the generated code. The following link discusses adding comments to the generated code a bit more:

https://www.mathworks.com/help/releases/R2019a/ecoder/ug/add-custom-comments-for-signal-or-parameter-identifier.html

By changing the storage classes for your Simulink.Signal objects, you should be able to get the comments to appear in the generated code. For example, if you change the Simulink.Signal object which represents the signal to have a storage class of 'ExportedGlobal', you will notice that now a variable is declared for that object and the comment exists. For more information about different types of storage classes, please refer to the following link:

https://www.mathworks.com/help/releases/R2019a/ecoder/ug/choose-a-built-in-storage-class-for-controlling-data-representation-in-the-generated-code.html

Please note that in order to use storage classes other than 'Auto', the Simulink.Signal must be defined outside of the model workspace (it should be in the base workspace).

If you are curious about how the generated code will store internal signal, state, and parameter data by default, please read through the following link:

https://www.mathworks.com/help/releases/R2019a/rtw/ug/how-generated-code-stores-internal-signal-state-and-parameter-data.html

Related Solutions

MATLAB: How to create signals that have specific attributes in Simulink 7.4 (R2009b)

To assign and validate signal attributes in a model, use the Simulink.Signal class to define a signal object in the MATLAB workspace. This will allow you to define your signal with specific attributes. You can also use this signal object to initialize a signal in your model. To do this, follow these steps:

1) Define a Simulink.Signal object in the workspace:

mySig = Simulink.Signal
mySig.RTWInfo.StorageClass = 'ExportedGlobal'  % Set its storage class to 'ExportedGlobal'
mySig.InitialValue = '10' % Set the signal's initial value

2) In your model, select a signal to validate against MySig object. Right click on a signal, choose signal properties and name the signal as mySig. Check the 'Signal name must resolve to Simulink.Signal object' option.

To learn more about Simulink.Signal objects, please refer to:

https://www.mathworks.com/help/releases/R2012b/simulink/slref/simulink.signal.html

MATLAB: Is it possible to append a pragma to a variable declaration in the code generated by Embedded Coder

There is no direct way to achieve the code that you are looking for. The best way is to implement a TLC-based custom storage class. A good place to begin doing this is by referring to the following documentation link:

https://www.mathworks.com/help/ecoder/ug/define-advanced-custom-storage-classes-types.html?s_tid=srchtitle

TLC-based custom storage classes are a little tricky to develop and need to be very specific to the customer's use case. In such instances, the recommendation is to consider engaging with the Consulting services provided by MathWorks.

Best Answer

Related Solutions

MATLAB: How to create signals that have specific attributes in Simulink 7.4 (R2009b)

MATLAB: Is it possible to append a pragma to a variable declaration in the code generated by Embedded Coder

Related Question